水通道蛋白PIP1基因过表达杨树的光合生理过程对干旱和复水的响应

doi:10.11707/j.1001-7488.20200208

Abstract

Abstract:

Objective: The responses of photosynthetic process to drought stress and re-watering of the wild type and PtPIP1;3(GenBank accession No. MN795092 ptopip1.3) transgenic poplar variety '84K' (Populus alba×P. glandulosa '84K') were compared to analyze the limitation factors to photosynthesis in order to further understand the function of aquaporin PIP1 in regulation of CO₂ conductance and the influences on photosynthesis. Method: The wild type and PtPIP1;3 transgenic poplar variety '84K' were subjected to severe drought stress (The soil water content reaches 35% of the field water capacity) and re-watering. The gas exchanges and chlorophyll fluorescence parameters of the leaves were measured, with which the mesophyll conductance (g_m) and other relevant parameters were calculated. Then the regulation of aquaporin in CO₂ conductance and photosynthesis after drought stress and re-watering was analyzed. Result: Net photosynthetic rate (P_n), stomatal conductance (g_s) and transpiration rate (Tr) of transgenic poplars were significantly higher than those of wild type plants under normal watering regime. After six days of drought treatment, P_n of transgenic and wild type poplars started to decrease significantly, and the former decreased more rapidly than the latter and reached to the same level of the latter's on day 7 and the remaining time of drought treatment. During the 7-10 days of drought treatment, g_s, g_mand P_n of transgenic and wild type poplars were significantly lower than their own control (normally watered plants). So did photochemical quenching(q_P), actual photochemical efficiency of photosystem Ⅱ(Ф_PSII), electron transport rate(J_flu), Rubisco maximum carboxylation rate(V_cmax)and maximum electron transport rate(J_max). Photosynthesis of transgenic and wild type poplars were mainly limited by mesophyll conductance. After three days of re-watering, photosynthesis of transgenic poplars recovered more quickly and chlorophyll fluorescence parameters restored to the normal level, whereas, chlorophyll fluorescence of wild type poplars did not fully recover. Mesophyll conductance was still the main limitation factor, while biochemical limitation was the second major limitation factor. Conclusion: Mesophyll conductance was the main limitation factor of photosynthesis of PtPIP1;3 transgenic and wild type poplar '84K' during drought stress and re-watering. The photosynthesis of PtPIP1;3 transgenic poplar recovered quickly with re-watering after drought stress including the recovery of photosynthesis system II, which might help plants survive in nature wherein the stress stimuli is often transient but periodical.

Key words: poplar, mesophyll conductance, photosynthesis limitation, aquaporin

CLC Number:

S718.43

Wenxin Liu,Zhicheng Chen,Yongxin Dai,Xianchong Wan. Responses of Photosynthetic Physiological Process of a Poplar with Overexpressed PIP1 Gene to Drought Stress and Rehydration[J]. Scientia Silvae Sinicae, 2020, 56(2): 69-78.

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处理 Treatment	g_m/ (mol CO₂·m^-2s^-1)	V_cmax/ (μmol CO₂· m^-2s^-1)	J_max/ (μmol· m^-2s^-1)	C_c/ (μmol CO₂·mol^-1)
野生型WT-S	0.007±0.003 b	13±1.8 b	45±4.2 b	51±4.9 b
野生型WT-CK	0.100±0.012 a	37±8.8 a	98±1.3 a	122±12.5 a
野生型WT-RE1	0.047±0.006 b	18±4.4 b	54±4.9 b	98±10.2 a
野生型WT-CK	0.116±0.014 a	39±4.8 a	97±3.5 a	116±13.2 a
野生型WT-RE2	0.052±0.004 b	24±12.4 b	55±4.6 b	123±20.1 a
野生型WT-CK	0.106±0.005 a	37±5.8 a	98±3.8 a	118±8.7 a
野生型WT-RE3	0.069±0.004 b	29±0.5 b	58±0.1 b	150±6.7 a
野生型WT-CK	0.096±0.010 a	41±2.1 a	88±1.2 a	120±9.9 b
过表达PB13-S	0.002±0 b	10±0.2 b	35±6.3 b	44±0.4 b
过表达PB13-CK	0.141±0.021 a	53±11.5 a	126±0.2 a	157±9.4 a
过表达PB13-RE1	0.174±0.001 a	35±6.9 b	108±4.0 b	187±2.9 a
过表达PB13-CK	0.136±0.017 b	54±4.1 a	120±3.2 a	151±15.7 b
过表达PB13-RE2	0.139±0.011 a	37±1.0 b	105±5.3 b	176±15.7 a
过表达PB13-CK	0.140±0.014 a	55±3.4 a	121±2.8 a	155±15.5 b
过表达PB13-RE3	0.098±0.003 b	39±0.6 b	113±4.2 b	138±11.8 b
过表达PB13-CK	0.130±0.017 a	59±4.1 a	123±4.6 a	155±15.4 a

处理 Treatments	基因型 Gene type	气孔限制 Stomatal limitation (l_s)(%)	叶肉导度限制 Mesophyll conductance limitation (l_m)(%)	生物化学限制 Biochemical limitation (l_b)(%)
对照Control	野生型WT	19.6±2.0	45.0±2.7	35.4±0.7
对照Control	过表达PB13	39.0±2.9	45.9±4.2	15.0±1.3
胁迫Stress	野生型WT	18.4±3.4	76.2±3.2	5.5±0.2
胁迫Stress	过表达PB13	6.5±0.5	88.9±0.2	4.6±0.7
复水1 RE-1	野生型WT	17.9±4.7	30.6±2.4	51.5±2.4
复水1 RE-1	过表达PB13	22.6±1.5	18.8±3.2	58.6±3.1
复水2 RE-2	野生型WT	18.2±2.8	49.2±3.3	32.6±0.5
复水2 RE-2	过表达PB13	24.1±3.3	27.3±0.9	48.6±4.2
复水3 RE-3	野生型WT	24.0±1.7	38.9±0.1	37.1±1.8
复水3 RE-3	过表达PB13	24.3±2.1	45.1±1.2	30.7±1.1

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Responses of Photosynthetic Physiological Process of a Poplar with Overexpressed PIP1 Gene to Drought Stress and Rehydration

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